Opinions: Fast-ratio manual steering, suspension upgrades
16:1 box: efficiently drains all the fun and pleasure out of driving the car.
Kinda how I feel about driving a /6 "musclecar". :p
The steering ratio controls the mechanical advantage. You're trading effort for the amount of turns on the wheel. The stock 24:1 manual steering box is ~5.5 turns lock-to-lock. A 20:1 box is ~4.5 turns lock-to-lock, and if you guessed a 16:1 box is roughly 3.5 turns lock-to-lock you'd be right. The 16:1 box is the same ratio as the power steering box, just without the "boost".
The 16:1 box is great as long as you're going more than 10mph. Very responsive, really lets you feel the road and the car reacts very quickly to steering inputs. Even with +7* of caster and 275's up front it's no big effort at all as long as you're moving at a decent speed. It's good at 30+mph, and at 50+ the steering feel isn't even heavy IMO, I like it. Now, below 10mph, it requires some significant effort. Below 5mph and it's a workout. And you're not turning the wheels if you're not rolling. But then, you
SHOULDN'T be turning the wheels if they're not rolling anyway if you like your tires and steering components. It's easy to forget that with power steering, since you can steer lock to lock at a standstill with your pinky finger. But the loads on the steering components on the other side of the steering box are the same as with a 16:1 manual box.
So really, you just have to ask yourself how often you're going less than 10mph and how much steering you're doing at those speeds. I wouldn't do 16:1 manual steering on a car I was parallel parking everyday, at least not with my Dusters tire and alignment set up. But less tire on the road and less caster make a big difference too, as does the weight of the car. My '74 Duster is likely a decent amount heavier than the OP's early A.